1. Biology: Exploring Life
Chapter 1
Biology: Exploring Life

2. What is Biology Biology can be defined as the study of Life
“Bio” means Life and “ology” means Study Of
It is a branch of science and a way of studying nature.

3. What is a biologist
A Biologist is a person who strives to understand, explain and describe the natural world of living things.
Biologists try to answer questions about
The number of organisms
The kinds of organisms
The rate of reproduction
The relationships among all organisms
Biologists focus on questions that deal with how life works not why should there be life.

4. Why Study Biology Biology is relevant
Great advances have been made in controlling and treating diseases caused by viruses, bacteria, parasites and organ failure
Agricultural Biologists use bioengineering to develop new genetically enhanced pest resistant crops
In making decisions about where to locate new living spaces for an ever increasing human population
In bridging the gap between biology and technology related careers in the biotech fields of laboratory science and applied ecology.

5. THE SCOPE OF BIOLOGY
Life’s levels of organization define the scope of biology
Life’s structural hierarchy
Defines the scope of biology, the scientific study of life
Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Organ system
Nervous system
Organ
Brain
Tissue
Nervous tissue
Cell
Nerve cell
Organelle
Nucleus
Molecule
DNA
Atom
Spinal cord
Nerve

6. All the living organisms in an ecosystem
An ecosystem consists of all the organisms living in a par ticular area
As well as the nonliving environmental components
All the living organisms in an ecosystem
Make up a community

7. An individual living entity
A population
Consists of a localized group of individuals of a species
An individual living entity
Is an organism

8. The hierarchy continues downward with
The hierarchy continues downward with
Organ systems
Organs
Tissues
Cells
Organelles
Molecules
Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Organ system
Nervous system
Organ
Brain
Tissue
Nervous tissue
Cell
Nerve cell
Organelle
Nucleus
Molecule
DNA
Atom
Spinal cord
Nerve

9. Living organisms and their environments form interconnecting webs
Ecosystems are characterized by the cycling of chemical nutrients from the atmosphere and soil
To producers to consumers to decomposers and back to the environment
Sun
Air
CO2 O2
H2O
Chemical
energy
Inflow of
light
Loss
heat
Producers
Cycling
nutrients
Consumers
Decomposers
Soil
Ecosystem

10. Energy flows one-way through an ecosystem
Energy flows one-way through an ecosystem
From the sun to producers to consumers and exits as heat
Sun
Air
CO2 O2
H2O
Chemical
energy
Inflow of
light
Loss
heat
Producers
Cycling
nutrients
Consumers
Decomposers
Soil
Ecosystem
Figure 1.2

11. Cells are the structural and functional units of life
Cells are the structural and functional units of life
A cell
Is the basic unit of life

12. New proper ties emerge
From the complex organization of a system, such as a cell

13. Eukaryotic cells Prokaryotic cells
Eukaryotic cells
Contain membrane-enclosed organelles, including a DNA-containing nucleus
Prokaryotic cells
Lack such organelles
Nucleus
(contains DNA)
Eukar yotic
cell
Prokar yotic cell
DNA
(no nucleus)
Organelles
25,000 
Figure 1.3

14. EVOLUTION, UNITY, AND DIVERSITY
The unity of life: All forms of life have common features
DNA is the genetic information
For constructing the molecules that make up cells and organisms

15. Each species’ genetic instructions
Each species’ genetic instructions
Are coded in the sequences of the four building blocks making up DNA’s two helically coiled chains A C T G

16. All organisms share a common set of features
All organisms share a common set of features
Ordered structures
Regulation of internal conditions
Figure 1.4B
Figure 1.4C

17. Growth and development Energy use Response to environmental stimuli
Growth and development
Energy use
Response to environmental stimuli
The ability to reproduce and evolve
Figure 1.4D
Figure 1.4E

18. The diversity of life can be arranged into three domains
The diversity of life can be arranged into three domains
Organisms are grouped (classified)
Into the prokaryotic domains Bacteria and Archaea and the eukaryotic domain Eukarya

19. Domains Bacteria and Archaea
Domains Bacteria and Archaea
SEM 25,000
Figure 1.5B
SEM 3,250
Figure 1.5A

20. Domain Eukarya includes
Domain Eukarya includes
Protists (protozoans and algae, falling into multiple kingdoms)
The kingdoms Fungi, Plantae, and Animalia
Kingdom Fungi
275
Kingdom Animalia
Protists
(multiple kingdoms)
Kingdom
Plantae
Figure 1.5C

21. Evolution explains the unity and diversity of life
Evolution explains the unity and diversity of life
Charles Dar win
Synthesized the theory of evolution by natural selection

22. Natural selection is an editing mechanism
Natural selection is an editing mechanism
That occurs when populations or organisms, having inherited variations, are exposed to environmental factors that favor the reproductive success of some individuals over others 1 2 3
Populations with varied inherited traits
Elimination of individuals with certain traits
Reproduction of survivors
Figure 1.6B

23. All organisms have adaptations
All organisms have adaptations
That have evolved by means of natural selection
Killer whale
Pangolin
Figure 1.6C

24. THE PROCESS OF SCIENCE
Scientists use two main approaches to learn about nature
Science
Is a way of knowing
Seeks natural causes for natural phenomena

25. Discovery Science In discovery science
Discovery Science
In discovery science
Scientists describe some aspect of the world and use inductive reasoning to draw general conclusion.

26. With hypothesis-based science, we pose and test hypotheses
With hypothesis-based science, we pose and test hypotheses
Hypothesis-based science involves
Obser vations, questions, hypotheses as tentative answers to questions
Deductions leading to predictions, and then tests of predictions to see if a hypothesis is falsifiable (Deductions are based on previous research and reliable fact based information).

27. A Case Study from Ever yday Life
A Case Study from Ever yday Life
Deductive reasoning is used in testing hypotheses as follows
If a hypothesis is correct, and we test it, then we can expect a par ticular outcome
Observations
Question
Hypothesis # 1:
Dead batteries
Hypothesis # 2:
Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Replacing bulb
Test prediction
Test falsifies hypothesis
Test does not falsify hypothesis
Figure 1.8A

28. Percent of total attacks
A Case Study of Hypothesis-Based Science
In experiments designed to test hypotheses
The use of control groups and experimental groups helps to control variables
Percent of total attacks
on artificial snakes
100 80 60 40 20
83%
17%
16%
84%
Artificial king snakes
Artificial brown snakes
Coral snakes
absent
present
Figure 1.8B
Figure 1.8C
Bar Graph-comparison of individual groups at one point in time

29. Biology is connected to many impor tant issues in our lives
Biology is connected to many impor tant issues in our lives
Environmental problems and solutions
Genetic engineering
Medicine
Figure 1.9

30. Many technological advances
Many technological advances
Stem from scientific research
The development of medicines to treat illness
The development of devices to see inside of the human body
The science-technology-society relationship
Is an impor tant aspect of a biology course
Enables students and their families to make intelligent decisions about health care
Development of goods and services to improve the living standard throughout the world